It's important to note this is not a peer-reviewed publication, this is just some document that has been shared. While the author has a doctorate in theoretical physics, and has extensive experience in that field, their Wikipedia article also has the following line:
> Hossenfelder's more recent content has received criticism for her attacks on academic research[13][14] and for conspiracy theory-style portrayals of the physics community.
(The author recently had their affiliation end with the Ludwig Maximilian University of Munich, and is not happy about it.)
I don't know remotely enough to comment on the author's statements or research, or on the contents of this document, but I would advise caution on getting too excited over significant developments that haven't yet been peer reviewed.
It can be valid without being peer-reviewed, but it isn't automatically reliable. Regardless of whether it has been tested, it could be fundamentally invalid. I don't know that it is, I don't know enough about the field to understand what's being said, my point is that the standards to have a pre-print aren't high. They're meant to keep out garbage, not to make sure that something is reasonable.
> Hossenfelder's more recent content has received criticism for her attacks on academic research[13][14] and for conspiracy theory-style portrayals of the physics community.
(The author recently had their affiliation end with the Ludwig Maximilian University of Munich, and is not happy about it.)
I don't know remotely enough to comment on the author's statements or research, or on the contents of this document, but I would advise caution on getting too excited over significant developments that haven't yet been peer reviewed.
Relevant XKCD: https://xkcd.com/2304/